Liquid detergent products are often considered to be more convenient to use than are dry powdered or particulate detergent products. Liquid detergents have therefore found substantial favor with consumers. Such liquid detergent products are readily measurable, speedily dissolved in the wash water, capable of being easily applied in concentrated solutions or dispersions to soiled areas on garments to be laundered and are non dusting. They also usually occupy less storage space than granular products. Additionally, liquid detergents may have incorporated in their formulations materials which could not withstand drying operations without deterioration, which operations are often employed in the manufacture of particulate or granular detergent products.
Liquid detergent products in terms of their most basic components will generally essentially comprise functional ingredients such as one or more surface active agents (surfactants) that promote and facilitate the removal of stains and soils from fabrics laundered in aqueous wash solutions formed from such liquid detergent products. Liquid detergent products will also generally contain a liquid carrier such as water which serves to dissolve or at least suspend the essential functional surfactant ingredients.
In addition to surfactants and a carrier liquid, heavy duty liquid detergent products can also contain a wide variety of additional functional ingredients which serve to boost the fabric cleaning effectiveness of the products into which they are incorporated. Such additional functional ingredients can include, for example, various detergent builders, chelating agents bleaching agents, bleach activators or catalysts, detergent enzymes, enzyme stabilizers, grease/oil solvents, dye transfer inhibition agents, pH controllers, brighteners and the like. While such additional composition components can enhance composition cleaning performance, such additional functional materials can also be relatively expensive, thereby driving up the cost of manufacture of such products and ultimately driving up the cost of such products to the consumer.
Liquid detergent products may also contain other types of additional ingredients which do not necessarily enhance the cleaning performance of such products but which may be useful for improving the physical stability or the aesthetics of such products. Such non-functional ingredients include a wide variety of materials such as hydrotropes, additional solvents, phase stabilizers, thickeners, suds suppressors, perfumes, dyes and the like. Again, while such non-functional ingredients can beneficially affect the stability or appearance of detergent products containing them, such non-functional ingredients also add cost to the product without necessarily serving to improve the fabric cleaning performance thereof.
One especially fruitful avenue for cheaply improving HDL aesthetics lies in the area of composition viscosity enhancing agents. It is, of course, advantageous to thicken dilute HDLs in order to avoid the thin, watery appearance that such highly aqueous products would normally have. Since using large amounts of thickener or using relatively expensive thickeners will undesirably drive up the cost of such HDLs, it would be advantageous to identify thickening agents which are relatively cheap and/or which can be usefully employed in relatively low concentrations. It would also be desirable to identify compounds such as certain surfactants and/or perfumes materials which, in addition to their usual function, can also serve to enhance product viscosity. HDL products which utilize relatively inexpensive thickening agents are described for example in Dauderman et al; U.S. Pat. No. 5,565,135; Issued Oct. 15, 1996 and in Dauderman et al; U.S. Pat. No. 5,587,356; Issued Dec. 24, 1996.
Given the foregoing considerations, it is highly desirable when formulating liquid detergent products to arrive at a proper balance of such competing factors as composition cost, composition cleaning performance and composition stability or aesthetics. Notwithstanding the existence of products such as those described in the '135 and '356 U.S. patents hereinbefore referenced, there remains a continuing need to identify heavy duty liquid laundry detergents with ingredients selected to provide suitably effective stain/soil removal from fabrics laundered therewith and to provide suitable product viscosity and other aesthetics while at the same time keeping the cost of such products very low. Accordingly, it is an object of the present invention to formulate heavy duty liquid laundry detergent compositions containing relatively small amounts of certain selected aromatic-based surfactants and a selected cost effective product thickening system along with very high concentrations of the most cost effective liquid detergent carrier--water.
It is a further object of the present invention to provide such liquid detergent compositions containing only minimal amounts of additional, relatively costly functional cleaning performance-enhancing ingredients.
It is the further object of the present invention to provide such liquid detergent compositions which also contain only minimal amounts of additional, relatively costly non-functional stability- or aesthetics-enhancing ingredients.